Lying at home because having only half rent (9)
I believe the answer is:
insincere
'lying' is the definition.
(thesaurus)
'home because having only half rent' is the wordplay.
'home' becomes 'in' ('he's home' can mean 'he's in').
'because' becomes 'since' (I've seen this in another clue).
'having' says to put letters next to each other.
'only half' suggests halving the letters.
'rent' halved is 're'.
'in'+'since'+'re'='INSINCERE'
'at' is the link.
(Other definitions for insincere that I've seen before include "may be laying it on" , "Not expressing genuine feelings" , "False, hypocritical" , "Not genuine, hypocritical" , "Deceitful, not genuine" .)